1. Field of the Invention
The present invention relates to a multi-lamp projection display apparatus using a plurality of lamps as a light source, particularly a multi-lamp projection display apparatus capable of managing the operating times and the like of the respective lamps without an error even if the lamps are replaced with new ones or interchanged with each other.
2. Description of the Related Art
Heretofore, projectors (projection display apparatuses) using a lamp as light sources have been designed to have a control circuit therein. For displaying a warning message before the lamp reaches the end of product's life, or the like, such control circuit stores the operating time of the lamp (period from light-on to light-off) cumulatively in a nonvolatile memory installed in the projector. The user may reset the cumulative time when replacing the lamp with a new one. Such a user's operation allows the control circuit to reset the operating-time information stored in the nonvolatile memory to zero.
However, the reset operation, which is carried out by the user every time he or she replaces the lamp, is complicated. In addition, when the reset operation is not carried out even at the time of replacement, the operating time of the lamp after the replacement is added to the last operating time of the lamp before the replacement. On the other hand, when the reset operation is carried out accidentally at the time of any event other than the replacement, the present information about the operating time of the lamp is wiped out.
Furthermore, in order to increase luminance, multi-lamp projectors with two or more lamps as their light sources have been developed in recent years. Any of such projectors may have a need for replacing only one of the lamps with a new one. Thus, when the reset operation is carried out on such a projector just as in the case with the aforementioned projectors, the user should remember which lamp is replaced and then reset the operating time of the lamp. In the multi-lamp projector, therefore, the reset operation is more complicated and leads to an increase in possibility of wrong operation (e.g., a reset operation is accidentally carried out on the operating time of any of the remaining lamps without replacement).
Japanese Unexamined Patent Application Publication No. H08-220637 proposes a projector with a holding mechanism for holding a lamp in a replaceable manner. Such a holding mechanism has a nonvolatile memory held with the lamp. The control circuit in the projector stores information about the operating time of the lamp or the like in the memory. According to a technology described in Japanese Unexamined Patent Application Publication No. H08-220637, the lamp can be replaced with a new one with the replacement of its accompanying nonvolatile memory in which the information about the operating time of the lamp is stored. Therefore, the reset operation at the time of the lamp replacement can be omitted.